In a positive sign for both companies, though, U.S. volumes of carbonated soft drinks barely dipped in 2018 after more than a decade of steeper declines, industry tracker Beverage Digest reported Wednesday.

Overall, U.S. carbonated soft drink volumes dipped 0.1%, the smallest decline in 14 years. The decline would have been larger if it hadn’t been for energy drinks like Monster and Red Bull, which continue to post growth.

Another good sign for the soda industry -- if not consumers: Prices for carbonated soft drinks rose 3.4% last year, more than the 2.6% increase in 2017, Beverage Digest estimated. Coke led the charge, helping lift overall soda sales in dollar terms.

"Coke has strong pricing power right now," said Duane Stanford, Beverage Digest’s executive editor. "They have a very strong market share. They took a price increase earlier last year than usual and they got good growth from brands like Coke Zero Sugar."

But he also cited slower declines for its main rival compared to 2017. "PepsiCo showed signs that increased marketing and advertising spend for core brands Pepsi, Dew and Gatorade could work to gain share lost to Coke in recent years," said Stanford.

Both companies have bigger problems than just each other. They’ve wrestled for years with U.S. consumers’ fading affections for traditional soft drinks, calories and artificial sweeteners. Coca-Cola and PepsiCo each raced to buy or concoct other drinks.

Although the declines in consumption leveled off last year, Stanford said it might take another year to see whether consumers truly have hit what he called a new normal.

Carbonated soft drinks remains by far the largest U.S. beverage category measured by dollar sales, even as more Americans turn to alternatives like bottled water and sports drinks.